This application claims priority to Korean Application No. 00-14552, filed Mar. 22, 2000, the disclosure of which is hereby incorporated herein by reference.
The present invention relates to wafer dryers and methods for drying wafers, and more particularly, to spin dryers for drying wafers and methods for using the same.
In a known method for drying a wafer such as a silicon wafer, the wafer is rotated at a high speed using a spin dryer to remove moisture from the surface of the wafer. Friction induced deterioration of high speed spinning parts of the spin dryer may generate particles. Also, particles which are removed from the wafer may be re-absorbed onto the wafer by static electricity induced by friction. Moreover, water marks may remain on the wafer in hydrophobic portions thereof after moisture is removed by the high speed rotation.
A widely used method for drying wafers larger than 8xe2x80x3 includes vaporizing isopropyl alcohol (IPA), which is hydrophilic and highly volatile, and removing moisture using the vapor. This method may provide a simple means for drying the wafer. However, reaction by-products such as particles ( e.g., silica) may be formed and coagulate on the wafer, leaving smears on the wafer. The particles may hamper the stability of follow-up processes. For example, locations where metal interconnections should be separated may be bridged by these particles, and intended connections may be broken by these particles. Moreover, as the diameter of the wafer is increased from 8xe2x80x3 to 12xe2x80x3, it becomes difficult to uniformly dry the entire wafer using only the isopropyl alcohol vapor.
According to embodiments of the present invention, a wafer dryer for drying a wafer includes a chamber and a support adapted to support the wafer in the chamber. A spray nozzle is disposed in the chamber. A source gas supply tank is in fluid communication with the spray nozzle. At least one heater is operable to heat the chamber and the source gas supply tank. A pumping line is in fluid communication with the chamber. Drive means are operable to rotate the chamber and the spray nozzle.
The drive means may be operable to rotate the chamber and the spray nozzle in opposite directions relative to one another. The at least one heater may include an external heater surrounding an upper portion of the chamber and operable to heat the chamber, and an internal heater mounted below the source gas supply tank and operable to heat the source gas supply tank. The wafer dryer may further include a fixed base and the drive means may include a chamber revolving unit operable to rotate the chamber about the fixed base, and a nozzle revolving unit operable to rotate the spray nozzle independently of the chamber.
According to further embodiments of the present invention, a wafer dryer for use with a wafer loading means includes a revolving chamber having a wall. The chamber has an interior and an exterior. A support is mounted on an upper part of the wall of the chamber. The support is adapted to support the wafer loading means in the chamber. An external heater surrounds an upper portion of the exterior of the chamber and is operable to heat the chamber. A revolving spray nozzle is disposed in the chamber and has a lower end. A source gas supply tank is connected to the lower end of the revolving spray nozzle by a source gas supply pipe. An internal heater is mounted below the source gas supply tank and is operable to heat the source gas supply tank. A fixed base is disposed below the internal heater. A pumping line passes through the fixed base. A chamber revolving unit is operable to rotate the chamber about the fixed base.
According to method embodiments of the present invention, a method for drying a wafer using a wafer dryer including a chamber and a revolving spray nozzle is provided. The method includes loading the wafer in the chamber. The pressure in the chamber in which the wafer is loaded is reduced to a near vacuum state. A temperature controlled atmosphere is created in the pressure-reduced chamber to quicken drying of the wafer. A source gas is sprayed on the wafer while rotating the chamber and the revolving spray nozzle in opposite directions in the pressure-reduced temperature controlled atmosphere.
Objects of the present invention will be appreciated by those of ordinary skill in the art from a reading of the figures and the detailed description of the preferred embodiments which follow, such description being merely illustrative of the present invention.